Process of sulfonation



July 29, 1958 L. v. BROWN 2,845,455

PRocEss oF sULFoNATIoN Filed ogm.. 5, 195e ATTORNEYS 2,845,455 PatentedgJuly 29, 1958 PROCESS oF SULFoNATIoN Lee V. Brown, Chicago, Ill., assignor to Sinclair Refining Company, New York, N. Y., a corporation of Maine Application October 5, 1956, Serial No. 614,232

2 Claims. (Cl. 260-504) This invention relates to the production of sulfonic acid oils known as mahogany sulfonic acid products. More particularly, it relates to the production of sulfonic acid oils by pretreating a petroleum stock with oleum and then sulfonatin'g the Vpretreated stock with S03.

Processes for sulfonating petroleum oil fractions by contacting them with sulfonating agents such as concentrated H2S04, oleum and S03 are well known. However, there are still associated with these processes, problems with respect to -obtaining high yields of. sulfonic acid oil not contaminated by colored or color-inducing vsubstances. Attempts to increase the yield of sulfonic acid products by increasing the concentration of the sulfonating agent are usually accompanied by a deterioration of the color due apparently to the increased formationof objectionable byproducts which are not readily separable from the acid oil. Also, high temperatures characteristic of sulfonation reactions employing high concentrations of the sulfonating agent, particularly sulfur trioxide, contribute to undesirable color and odor of the acid oil product.

It has now been found that relatively high yields of sulfonic acid oils substantially free from objectionable discoloration can be obtained by a two-stage sulfonation reaction in the rst stage of which the charge oil is contacted with a relatively small proportion of oleum at a relatively low temperature and in the second stage of which, after sludge removal, the partially sulfonated oil diluted with kerosene is further sulfonated by contact with S03 in admixture with S02. It has been'found that the preliminary partial sulfonation with oleum and removal of the heavy viscous acid sludge formed therein permits more uniform sulfonation of the diluted oil by means of S03 under conditions of close control of a relatively low temperature in the mainsulfonation reaction thereby providinghigher yields without color deterioration of the acid oil. Moreover, the character of the sludge provided in this sulfonation is such that it is easily handled even at the relatively low S03 sulfonation temperature. The limited amount of oleum in the preliminary sulfonation step provides more eiective use of the S03 in the main sulfonation zone and even though the acid sludge obtained in the preliminary sulfonation 1s heavy it is still workable.

Thus in accordance with this invention a petroleum hydrocarbon stock boiling in the range of about 600 to 1000 F. is contacted at a temperature of about A90-- 120? P. with about 2-8, preferably about 2-6, weight percent of about -25% oleum in a preliminary sulfonator. The viscous acid sludge formed by the ypreliminary sulfonation is separated and removed from the acid oil phase which is then diluted with kerosene, preferably about 1-5 parts by weight. To increase the ,compatibility of the nal sulfonate product in lubricating oil compositions, I prefer to use a kerosene having Ya specific dispersion of lessithan about 100. This kerosene Acan be obtained by highly acid-treating raw kerosene. The diluted acid oil phase, preferably at a temperature of 120-140 F., 1s

contacted with a suticient amount of a gaseous mixture of S03 and S03, having an S03 concentration of about 3-20 mole percent to maintain the reaction temperature within about 140-190 F., probably about 150 to 180 F., to effect further `sulfonation of the oil phase. Unreacted S03, S02 and kerosene vapors are separated and removed from the liquid products and ladditional acid sludge is separated and removed from the acid oil. The acid oil is degassed to remove primarily dissolved S03 thus permitting further -sludge precipitation. This further increment of acid sludge is separated and removed, and an acid oil, for instance, with a sludge content of about 0.1 to 0.2 volume percent is withdrawn. Sulfur dioxide is a by-product in the system and apparently it is formed as the result of a side reacti-on.

It has been found of particular advantage to pretreat the petroleum hydrocarbon stock with about 3 weight percent of about 20 percent oleum at about 100 F. to F. to form the viscous acid sludge. After separating and removing the viscous sludge from the oil phase, the oil phase is advantageously diluted with about 2 to 4 parts by weight of kerosene. Also advantageously a gaseous mixture of S03 and SO2 having an S03 concentration of about 5 to l0 mole percent is employed to complete the sulfonation. v

The process of the invention will now be described by reference to the accompanying drawing which represents a schematic diagram of the process and equipment employed.

In order to produce the S03 sulfonating agent, advantageously 30 percent oleum is transmitted by line 1 through heat exchanger 2 and thence introduced into still 3. In still 3 the 30 percent oleum is evaporated to produce S03 gas and 15-25 percent oleum. The S03 gas from still 3 is removed overhead by line 4. The oleum removed from still 3 flows by line 5 through heat exchanger 2 and thence into reactor 7. A portion of the oleum is removed by line 6 and ilows to a 98 percent sulfuric acid producing unit (not shown).

Charge oil is introduced by line 8 into reactor 7 where it is mixed with the oleum. The oleum-charge oil mixture is transmitted from reactor 7 by line 9 intosettler 10. The acid sludge formed by the reaction of the oleum and charge oil is separated from the oil phase in settler 10 and removed through line 11. The oil phase from settler 10 llows through line 12 and is diluted with kerosene from line 13. The kerosene diluted oil phase then ows into the top of sulfonation reactor 14. The S03 removed from still 3 by line 4 is diluted with SO2 from line 15 and is carried by the S02 through line 16 into the top of sulfonaton reactor 14.

The products from sulfonation reactor 14 ow into vapor disengager 17 where S03, S02 and kerosene vapors are separated from the liquid products and removed by lineV 18. The liquid products flow into settler 19 where the acid sludge is separated from the oil phase and removed'by line 20. The oil phase flows through line 21 into degassing-evaporator 22. Dissolved S02 gas is removed frorn the oil phase in evaporator 22 thus allowing the separation of additional acid sludge. The S03 is removed overheadvby line 23 while the oil phase flows through line 24 into settler 25. The acid sludge is separated from the oil phase in settler 25 and is removed byline 26 while the acid oil product ows out through line 27.

The acid oil ows through line 27 into reactor 29 where it is contacted with, for example, aqueous Ba(OH)2 from line 28. In reactor 29 the acid oil is neutralized to form a neutral sulfonate which flows by line 30 through heat exchanger 31 and thence into reactor 32 where it further reacts with the Ba(OH)2 t-o form a basic sulfonate.

The basic sulfonate ows through line 33 into settling tank 34 where unreacted Ba(0H)2 is settled out and recycled byline 35. The basic sulfonate then ows through line 36 to evaporator 37 where a portion of the kerosene diluent is removed overhead by line 38. The basic sulfonate is removed from evaporator 37 by line 39 and flows into slurry thickener 40 where the basic sulfonate solution is clarified and the suspended solids are thickened and returned to reactor 29 by line 41. The claried sulfonate solution is removed from slurry thickener 40 by line 42. The sulfonate solution in line 42 is heated by heat exchanger 43 before introduction into still 44. In still 44 the remaining major portion of the kerosene diluent is removed overhead by line 45. The basic sulfonate product is removed from still 44 by line 46.

The process of the invention is further illustrated by the following example in which reference is made to the drawing.

The S03 producing unit is charged with 30 percent oleum at 100 F. at the rate of 7,846 pounds per hour. The 30 percent oleum is preheated and introduced into the S03 evaporator or still which is maintained at 330 F. and p. s. i. g. The products obtained are 982 pounds per hour of S03 and 6,864 pounds per hour of 20 percent oleum. A portion of the percent oleum, at the rate of 208 pounds per hour is contacted with 6,549 pounds per hour of dewaxed sweet West Texas gas oil at 100 F. and 20 p. s. i. g. in reactor 7. The gas oil has the following properties.

Dewaxed sweet West Texas gas oil Gravity, API 26.1 Flash, F 390 Fire, F 455 SUS/100 F 216 SUS/210 F 46.2 Pour, F 10 Color (ASTM) 7- Specific dispersion 142.6 Sulfur, wt. percent 0.60 Moisture, wt. percent 0.0 Aniline pt., F 188 Refractive index/20 C 1.4990 Acid number 0.05 Ash (ASTM) 0.002

A viscous sludge is settled in settler 10 and removed at the rate of 607 pounds per hour.

At the rate of 15,000 pounds per hour SO2 gas is mixed with 982 pounds per hour of S03 gas produced above to form a dilute ve mole percent S03 gas mixture, which is then introduced into sulfonation reactor 14 where it is contacted with the pretreated charge oil from settler 10 owing at the rate of 6,150 pounds per hour. To facilitate the sulfonation reaction the pretreated oil is diluted with three parts .by weight of kerosene (18,450 pounds per hour) at 131 F. before introduction into reactor 14. The S03 sulfonation is carried out in a vertical baffle-plate section at 180 F. and 4 p. s. i. g. The products then ow to vapor disengager 17 and sludge separator 19 which are maintained at 180 F. in order to keep the sludge in a manageable state and thus facilitate handling. The sulfonation reaction in reactor 14 produces 90 barrels per hour of acid oil-kerosene which is removed by line 21. The acid oil thus formed is fed into degassing evaporator 22 maintained at 50 mm. Hg abs. and 165 F., wherein 324 pounds per hour of S02 and 670 pounds per hour of kerosene are removed from the acid oil thus permitting the separation of additional sludge. The degassed acid oil from evaporator 22 is processed in an electric separator where more sludge s separated and removed at the rate of 12.8 B. P. S. D. and providing 2020 B. P. S. D. of

a purified acid oil-kerosene solution. This solution can be extracted to separate the kerosene but preferably the solution is neutralized to produce petroleum sulfonates. The neutralization is advantageously carried out in two reaction stages, the first maintained at a relatively low temperature in order to avoid color deterioration of the basic sulfonate product.

Thus the 2020 B. P. S. D. of acid oil solution is fed into reactor 29, heated to 210 F. by steam coils, wherein it is mixed and reacted with an aqueous solution of Ba(0H)2. This solution is introduced at the rate of 3361 pounds per hour of BaO and 3016 pounds per hour of water. The acid oil solution is thus neutralized. The neutral sulfonate is then removed from reactor 29 and its temperature is elevated before introduction into second reactor 32 to permit the further reaction of the now neutral sulfonate and Ba(0H)2 at 275 F. and 20 p. s. i. g. This second reaction produces a basic sulfonate. The excess unreacted aqueous Ba(OH)2 is settled out in settling tank` at 275 F. and 30 p. s. i. g. The settled portionis removed at the rate of 2856 pounds per hour of BaO and 3016 pounds per hour of water and can be recycled. The basic sulfonate is then dehydrated by evaporating `a portion of the kerosene diluent (622 B. P. S. D.) in still 37 and the basic sulfonate is then thickened in slurry thickener 40. The basic sulfonate is withdrawn from thickener 40 at the rate of 1450 B. P. S. D. and after filtration, is preheated to 410 F. and introduced into kerosene topping still 44. Kerosene is removed overhead at the rate of 1035 B. P. S. D. leaving a product of 415 B. P. S. D. of basic barium sulfonate.

lt is claimed:

1. A method for the production of mahogany sulfonic acid products which comprises treating petroleum hydrocarbon stock boiling in the range of about 600 to 1000 F. with about 2 to 8 weight percent of about 15 to 25 percent oleum at a temperature of about to 120 F. to form a viscous acid sludge, separating and removing the viscous acid sludge from the oil phase, diluting the separated oil phase with kerosene, contacting the diluted oil phase with a sufficient amount of a gaseous mixture of S03 and S02 having an S03 concentration of about 3 to 20 mole percent to maintain a reaction temperature of about to 190 F. to effect further sulfonation of the oil phase, separating unreacted S03, S02 and kerosene vapors and separating and removing the acid sludge from the acid oil.`

2. A method for the production of mahogany sulfonic acid products which comprises treating a petroleum hydrocarbon stock boiling in the range of about 600 to 1000 F. with about 2 to 6 weight percent of about 15 to 25 percent oleum at about 100 F. to 110 F. thereby to form a viscous acid sludge, separating and removing the viscous acid sludge from the oil phase, diluting the separated oil phase with about 2 to 4 parts by weight of kerosene, contactingthe diluted oil phase at a temperature of about 120 to 140 F. with a sucient amount of a gaseous mixture of S03 and S02 having an S03 concentration Vof about 5 to 10 mole percent to maintain a sulfonation reaction temperature of about to 180 F. to etfect further sulfonation of the oil phase, separating and removing unreacted SO2, S03 and kerosene vapors, separating and removing the acid sludge from the acid oil, degassing the acid oil to remove dissolved S02 thus permitting further sludge separation, further separating and removing acid sludge to obtain an acid oil with a low sludge content.

References Cited in the file of this patent `UNITED STATES PATENTS 1,735,270 `Ls/iron@ Dec. 16, 1930 2,402,288 Lazar et al June 18, 1946 3,532,297 'A cohen Dec. 5, 195o 

1. A METHOD FOR THE PRODUCTION OF MAHOGANY SULFONIC ACID PRODUCTS WHICH COMPRISES TREATING PETROLEUM HYDROCARBON STOCK BOILING IN THE RANGE OF ABOUT 600* TO 1000* F. WITH ABOUT 2 TO 8 WEIGHT PERCENT OF ABOUT 15 TO 25 PERCENT OLEUM AT A TEMPERATURE OF ABOUT 90* TO 120*F. TO FORM A VISCOUS ACID SLUDGE, SEPARATING AND REMOVING THE VISCOUS ACID SLUDGE FROM THE OIL PHAW, DILUTING THE SEPARATED OIL PHASE WITH KEROSENE, CONTACTING THE DILUTED OIL PHASE WITH A SUFFICIENT AMOUNT OF A GASEOUS MIXTURE OF SO3 AND SO2 HAVING AN SO3 CONCENTRATION OF ABOUT 3 TO 20 MOLE PERCENT TO MAINTAIN A REACTION TEMPERATURE OF ABOUT 140* TO 190*F. TO EFFECT FURTHER SOLFONATION OF THE OIL PHASE, SEPARATING UNREACTED SO3, SO2 AND KEROSENE VAPORS AND SEPARATING AND REMOVING THE ACID SLUDGE FROM THE ACID OIL. 